Endoscopic system that uses overtube

ABSTRACT

With a first endoscope inserted through an overtube, the overtube is orally inserted into an object being examined, and a distal end portion of an insertion tube of the first endoscope is made to advance, within the object, from a jejunum via a jejunum-to-jejunum anastomosed portion and a jejunum-anastomosed bent portion so that the distal end portion is located adjacently to a Vater&#39;s papilla of a duodenum. The overtube is then sent to a position which is adjacent to the Vater&#39;s papilla along the insertion tube of the first endoscope. After this, the first endoscope is pulled from the overtube. A second endoscope is then inserted into the overtube to make a distal end portion of its insertion tube protrude from the distal end of the overtube and is located adjacently to the Vater&#39;s papilla. The second endoscope thus-approached is used to treat the Vater&#39;s papilla and the tissue therearound.

CROSS REFERENCES TO RELATED APPLICATION

This application is a divisional application of U.S. Ser. No. 11/732,804filed Apr. 4, 2007, the entire contents of which are incorporated hereinby reference.

BACKGROUND OF THE INVENTION

1. Technical Field of the Invention

The present invention relates to a therapeutic method and an endoscopicsystem which use an overtube, and in particular, to the therapeuticmethod and the endoscopic system which use an overture and which arepreferable to treatment on endoscopic retrogradecholangiopancreatography (ERCP) with patients who had a Roux-en-Yreconstructive operation.

2. Related Art

Endoscopic examinations and treatments for biliary disease and pancreasdisease, such as biliary tract cancer, pancreas cancer, cholelithiasis,and common bile duct stone, are progressing at a rapid pace. Compared tothe conventional surgical treatments, these examinations and treatmentsare less invasive and less burden on patients. The techniques for theseexaminations and treatments include endoscopic retrogradecholangiopancreatography (ERCP) and Endoscopic sphincterotomy. Theseendoscopic examinations and treatments are on the progress toapplications to postgastrectomy cases.

The difficulty level of procedures largely depends on reconstructionperformed after partial removal of the stomach or reconstructionperformed after the total gastric resection. As to the proceduraldifficulty level after the stomach reception, a Billroth Ireconstruction can be performed using the normal ERCP procedure.Meanwhile, in a Billroth II reconstruction and in the reconstructionperformed after the total gastric resection, it has been considered thatthe procedure related to the ERCP is higher in the difficulty level.

The Roux-en-Y reconstructive operation is most frequently used as thereconstructive operation for the total gastric resection. In thefollowing references, reported is a successful example of ERCP whichuses an endoscope-dedicated overtube for the small intestine in thetreatment of the common biliary duct stone on the Roux-en-Yreconstructive operation.

[Reference 1] Hirai et al., “An Oblique-viewing Endoscope with anOvertube Facilitate Bile Duct Stone Removal in Roux-en-Y GastrectomyPatients,” Gastroenterological Endoscopy 2006; 48: 212-217.

[Reference 2] Satoh et al., “3 cases of endoscopic treatments ofRoux-en-Y reconstructive stomach through papilla—Effectiveness ofOblique-viewing Endoscope and Small Intestine Overtube,” TherapeuticResearch for Hepato-Biliary-Pancreatic Diseases, Vol. 4 No. 1, page 88,2006.

These references show that the ERCP was performed with anoblique-viewing endoscope, in which the digestive tract was shortened bystretching operations of the endoscope, a small-intestine overtube wasmade to advance to suppress deformations of the digestive tract, andthen the endoscope was made to advance. It is reported that, thoughbeing in all of a few cases, repeating these operations allowed to theendoscope to reach the duodenum papilla.

For using procedures with an oblique-viewing endoscope or aforward-viewing endoscope, it is easier to insert the endoscope into anobject because the view in the inserting direction can be secured.However, in this case, it is difficult to perform treatment, because theview in the treating direction cannot be secured. Thus, it is easy forthe endoscope to pass the overtube through the jejunum-anastomosed bentportion and to reach the papilla, while it is difficult to treat thepapilla by the endoscope. If giving greater importance to easiness ofthe treatment of the papilla to the contrary, a side-viewing endoscopemay be used. However, for the side-viewing endoscope, the view in theinserting direction cannot be secured, resulting in a lessenedperformance for inserting the endoscope. As stated, it is considerablydifficult to make both the treatment and the inserting performanceeasier at the same time.

SUMMARY OF THE INVENTION

The present invention has been made in consideration of the problem thatthe foregoing overtubes for endoscopes has confronted, and has an objectto provide a therapeutic method and an endoscopic system which use anovertube, the method and system of which are able to enable an endoscopeto access the Vater's papilla of an Roux-en-Y gastrectomy patient in aspeedy, stable and easy manner after smoothly passing thejejunum-to-jejunum anastomosed portion and jejunum-anastomosed bentportion.

According to the present invention, as one aspect thereof, there isprovided an endoscopic system comprising: an overtube having aninsertion channel formed along an axial direction thereof; an endoscopeinserted into the insertion channel of the overtube for use thereof; andassist means for assisting, when the overtube is inserted adjacently toa jejunum-to-jejunum anastomosed portion of a jejunum of an object beingexamined in a state where the endoscope is kept being inserted into theinsertion channel of the overtube, changes of an insertion path alongwhich the overtube is inserted from the jejunum to thejejunum-to-jejunum anastomosed portion.

Furthermore, as another aspect of the present invention, there isprovided a method of either diagnosing or treating a Vater's papilla andtissue located adjacently thereto, comprising: a first step in which afirst endoscope is inserted into an insertion channel of an overtube; asecond step in which, with the first endoscope inserted through theinsertion channel of the overtube, the overtube is orally inserted intoan object being examined and a distal end portion of an insertion tubeof the first endoscope is located adjacently to a Vater's papilla of aduodenum of the object by making the distal end portion advance, in theobject, from a jejunum via a jejunum-to-jejunum anastomosed portion anda jejunum-anastomosed bent portion; a third step in which the overtubeis sent to a position adjacently to the Vater's papilla along aninsertion tube of the first endoscope; a fourth step in which the firstendoscope is pulled out of the insertion channel of the overtube; and afifth step in which a second endoscope is inserted into the insertionchannel of the overtube so as to enable a distal end portion of aninsertion tube of the second endoscope to be protruded from a distal endof the overtube and to position the distal end portion adjacently to theVater's papilla, the second endoscope being for diagnosis or treatmentof the Vater's papilla and the tissue located adjacently thereto.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a perspective view outlining the configuration of anendoscopic system according to a first embodiment of the presentinvention;

FIG. 2 is a side view taken along an A-A line in FIG. 1;

FIG. 3 is a sectional view taken along a B-B line in FIG. 1;

FIG. 4 is a partial sectional view explaining the geometricalrelationship between a balloon and an air-supply channel;

FIG. 5 explains a path from the stomach of a patient who had a Roux-en-Yreconstructive operation to the Vater's papilla thereof;

FIGS. 6-12 explain, respectively, how to approach the Vater's papilla inthe first embodiment;

FIG. 13 is a partial perspective view showing an overtube employed by anendoscopic system according to a second embodiment of the presentinvention;

FIG. 14 explains part of the processes to approach the Vater's papillain the second embodiment;

FIG. 15 explains part of the processes to approach the Vater's papillain a first modification;

FIG. 16 is a partial perspective view showing an overtube according to asecond modification;

FIG. 17 is a partial perspective view showing an overtube according to athird modification;

FIG. 18 is a partial perspective view showing a second endoscopeinserted in an overtube according to a fourth modification;

FIG. 19 is a partial perspective view showing an overtube according to afifth modification;

FIG. 20 is a partial perspective view showing an overtube according to asixth modification;

FIG. 21 explains part of the processes to approach the Vater's papillaaccording to the sixth modification;

FIG. 22 is a partial perspective view showing an overtube according to aseventh modification;

FIG. 23 explains part of the processes to approach the Vater's papillaaccording to the seventh modification;

FIG. 24 explains the positional relationship between a second endoscopeand an overtube, which is viewed axially in the seventh modification;

FIG. 25 is a partial perspective view showing an overtube according toan eighth modification;

FIG. 26 explains part of the processes to approach the Vater's papillaaccording to the eighth modification;

FIG. 27 is a partial perspective view showing an overtube according to aninth modification;

FIG. 28 explains part of the processes to approach the Vater's papillaaccording to the ninth modification;

FIG. 29 is a side view showing an overtube according to a tenthmodification;

FIG. 30 is a partial sectional view taken axially to show the structureof an overtube according to an eleventh modification;

FIG. 31 is a partial sectional view explaining the operations of a lockmechanism to an overtube in the eleventh modification;

FIG. 32 is a partial perspective view showing an overtube according to atwelfth modification;

FIG. 33 explains part of the processes to approach the Vater's papillaaccording to the twelfth modification;

FIG. 34 is a partial perspective view showing an overtube according to athirteenth modification;

FIG. 35 explains part of the processes to approach the Vater's papillaaccording to the thirteenth modification;

FIG. 36 is a partial perspective view showing an overtube according to afourteenth modification; and

FIG. 37 explains part of the processes to approach the Vater's papillaaccording to the fourteenth modification.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, referring to the accompanying drawings, various embodimentsand their modifications of an endoscopic system with an overtubeaccording to the present invention will now be described.

In the embodiments, an endoscopic system and a therapeutic procedurewhich use the overtube according to the present invention is applied toa pancreatic/biliary duct treatment (a treatment of pancreatic andbiliary ducts) to the Vater's papilla of a patient who had the Roux-en-Ygastrectomy, which is a reconstructive operation.

First Embodiment

Referring now to FIGS. 1-7, the endoscopic system and the therapeuticprocedure according to the first embodiment will now be described.

FIG. 1 shows the configuration of a primary part of the endoscopicsystem 1. As shown therein, the endoscopic system 1 is equipped with anovertube 11 on which a balloon is loaded, an air-supply device 12controlling the expansion and shrinkage of the balloon of the overtube11, and an endoscope 13 to be inserted together with the overtube 11into body cavities or tubular cavities of an object (for example, theduodenum subjected to oral insertion). The endoscope 13 has an insertiontube inserted into an insertion channel of the overtube 11, and with itsinserted state, the endoscope 13 is inserted into a body cavity or atubular cavity of the object such that the overtube 11 is led.

The overtube 11 is made of a resin material, such as polyurethane,thermoplastic elastomer, fluorinasted resin, or silicon. This overtube11 is provided with a flexible tubular portion 21 which is formed as awhole into a substantially cylindrical shape and has a bendablecharacteristic, a distal end portion 22 integrally formed with one end(distal end) of the flexible tubular portion 21, and a grip 23integrally formed with the other end of the flexible tubular portion 21.In the following, the side going towards the distal end portion 22 iscalled “distal end side,” while the side going towards the grip 23 iscalled “base end side.”

The flexible tubular portion 21 is a cylindrical member in which thereis formed an insertion channel P1, into which the insertion tube of theendoscope 13 is inserted. On the outer surface of the flexible tubularportion 21, a balloon 24 is mounted at a predetermined position in alongitudinal direction (hereinafter referred to as an “axial direction”)of the flexible tubular portion 21. This balloon 24 is a flexible thinbag member made of resin material (thermoplastic resin made of silicon,latex, polyurethane, or nylon) and air-tightly loaded on the outersurface of the flexible tubular portion 21. Thus the balloon 24 isproduced to selectively expand and shrink in response to supplying anddischarging air thereto and therefrom. The balloon 24 is thereforeexpanded to fixedly position the overtube 11 in a body cavity or atubular cavity of an object to be examined.

The whole body of the flexible tubular portion 21 or at least the distalend portion 22 is made of a material including an X-ray non-transmissionsubstance. Under the X-ray fluoroscopy, the existence of the X-raynon-transmission substance portion can be detected in a distinguishablemanner.

In addition, as shown in FIG. 2, on the flexible tubular portion 21, anarm-like air-supply mouth ring 26 and an arm-like water-supply mouthring 27 are formed. These mouth rings 26 and 27 are protruded from theouter surface of the flexible tubular portion 21 on the base-end sidethereof so that the positions of the mouth rings bisect thecircumference of the flexible tubular portion.

Of these, the water-supply mouth ring 26 is open from the innercircumferential surface of the flexible tubular portion 21, that is, tothe insertion channel P1 which is inside the flexible tubular portion.Hence, water (e.g., normal saline) supplied from a not-shownwater-supply source to the water-supply mouth ring 26 is subjected tomoistening the inner circumferential surface.

The air-supply mouth ring 27 is made to communicate with an air-supplychannel 26A (refer to FIG. 3) produced in the body of the flexibletubular portion 21. This air-supply channel 26A communicates with aninner cavity 24A of the balloon 24 (refer to FIG. 24). The air-supplymouth ring 26 is connected to an air-supply port 31 of the air-supplydevice 12 via a hose 30. The air-supply device 12 is equipped with anair-charge/discharge switch 32, which is operated to supply, forexample, air from the air-supply port 31. Hence when the air is suppliedfrom the air-supply device 12, the supplied air reaches the air-supplymouth ring 26 via the hose 30, and then reaches the inner cavity 24A ofthe balloon 24 via the air-supply channel 26A, expanding the balloon 24.This expanded state is pictorially illustrated by an imaginary line inFIG. 1. Further, the air-supply device 12 is equipped with a pressuredisplay monitor 33 that represents the pressure of the balloon 24.Alternatively a syringe to charge and discharge air may be used in placeof the air-supply device.

The inner cavity of the balloon 24 has a preset volume, which is allowedto expand up to a preset-size balloon in response to supplying air of apredetermined specified volume. The cubic capacity of the expandedballoon Is set to be adapted to different diameters of a target part(i.e., a body cavity or a tubular cavity) to which the balloon is fixed,wherein the different diameters absorb differences of individuals.

Meanwhile when the switch 32 is operated to discharge the air, the airin the balloon 24 is discharged through the path opposite to the above,thus shrinking the balloon 24. The shrunk balloon is pictorially shownby a solid line in FIG. 1. In this shrunk state, the balloon 24 istouched as a whole to the outer circumferential surface of the flexibletubular portion 21 so as to be almost flat thereon.

In the present embodiment, the shape and size of the balloon 24 aredecided such that the balloon 24 comes into contact with the inner wallsof each of the duodenum and the jejunum when a predetermined amount ofair is supplied into the balloon. The shape is defined by a diameter R(diameter including the diameter of the flexible tubular portion 21) andan axial length L of the balloon most expanded.

The endoscope 13 is provided with an elongated insertion tube 13A whichis flexible and an at-hand operation device 13B formed integrally withthe base end of the insertion tube 13A. The at-hand operation device 13Bis provided with various types of switches 41 and 42 for use in airsupply and water supply, an operation lever 43 for use in bending theinsertion tube 13A, a forceps cap 44 through which a therapeutic forceps(not shown) is inserted into the insertion tube 13A. A distal end,having a specified axial length, of the insertion tube 13A is rigid andformed as a distal end portion 45 and a CCD camera and a lighting source(both not shown) are embedded in the distal end portion 45. Further, theinsertion tube 13A has a bendable portion 46 positioned next to thedistal end portion 45. The bendable portion 46 operates to respond towires which go forward and backward selectively in response tooperator's operations at the operation lever 43, so that, for example,the insertion tube 13A is bendable selectively in the upward, downward,rightward and leftward directions defined when being viewed along theaxial direction of the insertion tube.

In the present embodiment, the endoscope 13 is either a first endoscope13X or a second endoscope 13Y, which is used depending on purposes. Thefirst endoscope 13X is either a forward-viewing endoscope or anoblique-viewing endoscope and the second endoscope 13Y is a side-viewingendoscope. For generally indicating the endoscopes, a reference numeral“13” is simply used, and for distinguishably indicating “forwardviewing” or “oblique viewing” and “side viewing,” reference numerals“13X” and “13Y” are used selectively. The “forward viewing” is viewing aforehand view along the axial direction of the insertion tube of anendoscope, the “side viewing” is viewing in a direction substantiallyperpendicular to the foregoing axial direction, and the “obliqueviewing” is viewing in angles between the forward and side viewingdirections.

(Treatment Technique Including Approach to Vater's Papilla)

A Treatment Technique that Uses the Endoscope System according thepresent embodiment, which includes an approach to the Vater's papilla ofa patient (i.e., an object being treated), will now be described.

Prior to describing a practical treatment technique, a Roux-en-Ygastrectomy will now be explained briefly. This Roux-en-Y Gastrectomy isone of the reconstructive techniques used after totally or partlyresecting the stomach. In the Roux-en-Y reconstructive operation, themost part of the stomach or a part of the esophagus, which is adjacentto the cardia of the stomach, and a part of the duodenum, which isadjacent to the pylorus of the stomach, are resected. The stump of theduodenum is sealed. The jejunum connected to the duodenum fixed in theabdominal cavity by the ligament of Treitz is cut at a lower position ofthe ligament of Treitz. The anus-side jejunum divided by this cutportion is anastomosed (or inosculated) with the remaining stomach orthe esophagus. In addition, the jejunum connected with the duodenum,which is connected with the pancreas and the gallbladder, is anastomosedwith the jejunum anastomosed with the remaining stomach or theesophagus.

That is, as shown in FIG. 5, the jejunum F4 is connected with theremaining stomach F2 via a stomach-to-jejunum anastomosed portion F3 andalso the jejunum F4 is connected with the duodenum F7 via ajejunum-to-jejunum anastomosed portion F5 and a jejunum-anastomosed bentportion F6. In general the jejunum-anastomosed bent portion F6 ischaracteristic of being narrower. Additionally, a part ranging from thejejunum-to-jejunum anastomosed portion F5 to the stump of the duodenumvia the jejunum-anastomosed bent portion F6 and the Vater's papilla F8is called an afferent loop F9. One of the characteristics of theRoux-en-Y reconstruction is that the afferent loop F9 is longer.

Thus, when an endoscopic treatment of pancreatic duct and biliary ductis performed with a Roux-en-Y gastrectomy patient, it is necessary thatthe thin and long insertion tube of an endoscope is orally inserted theesophagus Fl of the patient such that the insertion tube pass thestomach F2 and is inserted into the afferent loop F9 via thejejunum-to-jejunum anastomosed portion F5. And it is necessary that theinsertion tube should advance retrogradely in the afferent loop F9.

In the present embodiment, the treatment technique that considers thosecircumstances is provided, which will now be detailed with referenced toFIGS. 6-11, with focusing an approach to the Vater's papilla.

(Approach to Vater's Papilla (Approach Procedure))

First a doctor inserts the insertion tube 13A of the first endoscope 13Xinto the insertion channel P1 of the overtube 11. At this stage, theballoon 24 is in its shrunk state. Before this insertion, water issupplied from the overtube 11 or the water-supply port 27 via thewater-supply mouth ring 27 of the overtube 11 or a not-shownwater-supply channel through the distal end of the insertion tube 13A ofthe first endoscope 13X, so that the wall surface of the insertionchannel P1 is moistened. Hence the passing performance for inserting andpulling the insertion tube 13A through the insertion channel P1improves, providing an improved operability. After this water supply,the insertion tube 13A is inserted into the insertion channel P1, andthe distal end portion 45 of the insertion tube 13A is made to slightlyprotrude from the distal end portion 22 of the overtube 11 (refer to adashed-two dotted line depicted in FIG. 1). This provides a field ofview to a CCD camera of the insertion tube 13A.

In this inserted state, as shown in FIG. 6, as observing forward-viewingimages from the first endoscope 13X, the doctor orally inserts, via theesophagus F1 and the stomach F2, both the overtube 11 and the insertiontube 13A of the first endoscope 13X into the jejunum F4. And, as shownin FIG. 6, when the distal end portion 45 of the insertion tube 13reaches a position adjacent to the jejunum-to-jejunum anastomosedportion F5, the insertion is temporarily stopped. An alternativeinsertion way is that, with the overtube kept on the at-hand portion ofthe firs endoscope 13X, the first endoscope 13X is first inserted intothe jejunum F4, and then the overtube 11 is made to advance forward.

Then, as shown in FIG. 7, the doctor operates the switch 32 of theair-supply device 12 to supply a predetermined amount of fluid (air inthe embodiment) to the balloon 24 of the overtube 11. Responsively tothis air supply, the balloon 24 expands to have a predetermined innercavity volume, where the outer surface thereof is forced to partiallytouch the wall surface of the jejunum F4 in a tight manner. As a result,the balloon 24, i.e., overtube 11 is positionally fixed to the jejunumF4. In this positionally fixed state, the distal end of the insertiontube 13A of the first endoscope 13X, that is, the distal end portion 45tracks in its view the jejunum-to-jejunum anastomosed portion F5.

When the above state is established, the doctor operates the operationlever 43, which is equipped at the at-hand operation device 13B of thefirst endoscope 13X, in such a manner that the bendable portion 46 isbent to enable the distal end portion 45 of the insertion tube 13A to bedirected toward the jejunum-to-jejunum anastomosed portion F5. Thissituation is illustrated by a two-dotted dashed line in FIG. 7.Specifically, this bending operation becomes a subtle guide operationnecessary to smoothly feed the insertion tube 13A into thejejunum-to-jejunum anastomosed portion F5 which is opened almostperpendicularly to the jejunum F4. During this guide operation, both thebendable portion 46 and the distal end portion 45 are bent with the useof the balloon 24 of the overtube 11 as a fulcrum. This fulcrum ispositionally fixed to the jejunum F4, so that the bending operation isunlikely to have influence of peristalsis of the jejunum and/or thestomach, gaining steadiness and stableness in the bending operation.This guide operation surely positions the insertion tube 13A at theinlet of the afferent loop.

Though the jejunum-to-jejunum anastomosed portion F5, which is the inletof the afferent loop F9, is narrower, the insertion tube 13A can easilybe inserted into the afferent loop F9 with the aid of the positionalfixing function given by the balloon 24.

After the guide operation, in a state where the overtube 11 kept thereas it is, the doctor manually operates the insertion tube 13B so thatthe insertion tube is fed into the afferent loop F9. This insertion is afeeding operation carried out after the positioning operation by whichthe distal end portion of the insertion tube 13B, that is, the distalend portion 45, is already positioned to slightly intrude into thejejunum-to-jejunum anastomosed portion F5, that is, the afferent loopF9. Accordingly, the insertion tube 13A smoothly passes from thejejunum-to-jejunum anastomosed portion F5 to the jejunum-anastomosedbent portion F6 in response to operations at the insertion tube.

The foregoing feeding operations allow the insertion tube 13A of thefirst endoscope 13X to be penetrated into a deeper part in the afferentloop F9. Since the first endoscope 13X is either a forward-viewingendoscope or an oblique-viewing endoscope, endoscopic images presentedon the monitor are able to the Vater's papilla F8 which is located onand in the wall of the duodenum F7. Accordingly, with tracking thetubular cavity of the duodenum in the endoscopic images, the Vater'spapilla F8 can be searched, whereby the Vater's papilla can be foundeasily. When the distal end portion 45 arrives at a neighboring positionwith the Vater's papilla F8, the doctor stops to insert the insertiontube 13A any more, where the first endoscope 13X is kept there.

Then the doctor operates the switch 32 of the air-supply device 12 tohave the balloon 24 attached on the overtube 11 shrunk, and inserts theovertube 11 into the afferent loop F9 along the insertion tube 13A ofthe first endoscope 13X. This makes it possible to make the distal endof the overtube 11 arrive at a position neighboring the Vater's papillaF9, as shown in FIG. 9.

After this, the doctor operates to expand again the balloon 24 on theovertube 11, as shown in FIG. 10. Hence the balloon 24 is able totightly adhere to the wall of the duodenum F7 at a position before theVater's papilla F8, so that the balloon 24, i.e., overtube 11 ispositionally fixed to the duodenum F7. As illustrated in FIG. 11, thedoctor pulls both the overtube 11 and the first endoscope 13X at thesame time to try to shorten the jejunum F4, jejunum-to-jejunumanastomosed portion F5, and duodenum F7. This causes the overtube 11 andthe first endoscope 13X to be straight except their bendable portions.FIG. 11 shows the jejunum which is made shortened and straight.

The doctor then pulls back the first endoscope 13X from the overtube 11.Then, using the water-supply port 27 of the overtube 11 which has beenorally inserted and kept in the body, water is supplied into theinsertion channel P1. This water supply facilitates the insertion of asecond endoscope 13Y which will then be used. Together with this watersupply, the doctor inserts the second endoscope 13Y into the insertionchannel P1 of the overtube 11. It is preferred that water is suppliedinto the insertion channel P1 from even the second endoscope 13Y duringthe insertion of the second endoscope. The second endoscope 13Y is aside-viewing endoscope. As shown in FIG. 12, the second endoscope 13Y isguided by the overtube 11, so that the second endoscope can easily reacha position adjacent to the Vater's papilla F8.

The second endoscope 13Y provides side-viewing images of the Vater'spapilla F8. Using those side-viewing images, the doctor engages inendoscopic diagnosis and, if required, inserts a therapeutic instrumentthrough the forceps cap 44 to use the instrument for therapeutictreatments such as a treatment of pancreatic duct and biliary duct.

The second endoscope 13Y is a side-viewing endoscope equipped with anelevating device in its distal end portion 45, which elevating device isfor elevating a therapeutic instrument. Both the bendable portion 46 andthe distal end portion 45 of the second endoscope 13Y are operated onthe fixed positions of the balloon 24 of the overtube 11, where thefixed positions serve as a fulcrum. Thus the diagnosis and treatmentscan be made easier.

In this way, according to the endoscopic system 1 according to thepresent embodiment, the two types of endoscopes 13X and 13Y, which are aforward- or oblique-viewing type and a side-viewing type, can be usedfor purposes. Specifically, for the approach to the Vater's papilla F8,the first endoscope 13X is used dedicatedly, in which forward imagesalong the advancing direction are subjected to doctor's observation ininserting the overtube 11. Namely, the advantage of the forward- oroblique-viewing images can be utilized for approaching to the Vater'spapilla F8, which is easier for doctors in carrying out the approachingprocedure. When diagnosis and necessary treatments are performed withthe Vater's papilla F8, the second endoscope 13Y is used underside-viewing images, making the treatments easier.

In the former approach, the balloon 24 provides the positional fixingfunction between the overtube and the jejunum F4 at the position beforeand adjacent to the jejunum-to-jejunum anastomosed portion F5. Thanks tothis positional fixing function, when the insertion tube 13A of thefirst endoscope 13X is bent laterally toward the inlet of the afferentloop (i.e., the jejunum-to-jejunum anastomosed portion F5), thisdirectional change can be done in a stable and reliable manner. In otherwords, since the overtube 11 is positionally fixed within the body, theinsertion tube 13A of the endoscope 13X resists the influence caused bymotions of organs including the jejunum. Hence the operator's operationscan be a simple bending operation by which the distal end portion of theinsertion tube 13A is bent by a necessary amount of bending angle. Fordoctors, the operations at the operation lever 43 can be reflecteddirectly in changing the directions, facilitating the operations fordirectional changes toward the afferent loop F9.

In addition, by using the insertion tube 13A of the first endoscope 13Xas a lead, the overtube 11 is then fed along the insertion tube 13A.Hence feeding the overtube 11 can be facilitated.

Further, when the distal end of the overtube 11 is located at theVater's papilla F8, the balloon 26 is expanded again, thereby allowingthe distal end of the overtube 11 to be fixed positionally relative tothe duodenum F7. It is therefore prevented that organic motions resultin changing the position of the overtube 11 and falling off the overtube11. In a state where the distal end is positionally fixed in this way,the endoscope is replaced by a side-viewing type endoscope. This changein the types of the endoscopes can be facilitated and smoothed, owing tothe fact that the jejunum F4, jejunum-anastomosed bent portion F6, andduodenum F7 are already piled up by the overtube 11 to be straight inorder to secure an insertion route for the next endoscope and theinsertion route is positionally fixed by the balloon 24.

Accordingly, for patients who have the Roux-en-Y reconstructiveoperation, the access to the Vater's papilla F8 can be made speedier,more stable and easier after, as much as possible, smoothly passing thejejunum-to-jejunum anastomosed portion F5 and the jejunum-anastomosedbend portion F6.

Incidentally, the insertion tube of the first endoscope 13X may have afunction to change the hardness thereof. This function enhances theguide performance which is for feeding the overtube 11 into the afferentloop F9 deeply along the insertion tube 13A, making the feedingoperations easier.

Moreover, according to need, it is possible to pass over the positionfixing step carried out at the jejunum by expanding the balloon on theovertube 11, which step is shown in FIG. 7.

Second Embodiment

Referring to FIGS. 13-14, a second embodiment of the endoscopic systemaccording to the present embodiment will now be described.

Similarly to that in the first embodiment, an overtube 51 shown in FIG.13 is provided with a flexible tubular portion 52 being made of resinand having flexibility, a grip 53 formed integrally with an at-hand sideportion of the flexible tubular portion 52, and an air-supply mouth ring54A and a water-supply mouth ring 54B both formed on the flexibletubular portion 52. Further, the flexible tubular portion 52 has adistal end portion which is obliquely cut over a predetermined length“a” in the axial direction of the distal end portion, which distal endportion is provided as a distal end portion 51A having an obliqueopening. On the overtube 51, a balloon 55 made similarly to theforegoing one is loaded at a predetermined position shifted from thedistal end portion 51A toward the at-hand side.

An operator inserts the first endoscope 13X into the insertion channelof the overtube 51 and the first endoscope with the overtube is orallyinserted into the jejunum F4 of an object being examined. When theimages from the first endoscope 13X captures the jejunum-to-jejunumanastomosed portion F5 and the distal end portion 51A of the overtube 51reaches a position which is short of the jejunum-to-jejunum anastomosedportion F5, the operator manually rotates the overtube 51 on its axisdirection from a current unspecified angular position (refer to FIG.14(A)) to an angular position at which the oblique opening of the distalend portion 51A is oriented toward the jejunum-to-jejunum anastomosedportion F5 (refer to FIG. 14(B)).

This rotational operation may be performed with the use of a marker (notshown) applied on the grip 53 of the overtube 51 or the contour of thedistal end portion 51A captured in X-ray transmitted images when X-rayfluoroscopy is accompanied, as in ERCP.

After the rotational operation, the operator bends the insertion tube13A of the first endoscope 13X so that its distal end portion 45 isprotruded from the oblique opening of the distal end portion 51A, whichis now directed toward the jejunum-to-jejunum anastomosed portion F5,and oriented toward the jejunum-to-jejunum anastomosed portion F5. And,as shown in FIG. 14(C), while the insertion tube 13A is pushed forwardwith the oriented attitude so that the insertion tube 13A is insertedinto the afferent loop F9 beginning from the jejunum-to-jejunumanastomosed portion F5. The other steps in approaching to the Vater'spapilla F8 are similar or identical to those in the first embodiment.

In this way, when the oblique opening is directed toward thejejunum-to-jejunum anastomosed portion F5, the insertion tube 13A of thefirst endoscope 13X can be bent in a state where the distal end of theovertube 51 is located closer to the anastomosed portion F5. Thus theovertube 51 is given a more effective positional fixing function, sothat the overtube 51 can be inserted more smoothly under easieroperations. Additionally, in the present embodiment, since the overtube51 is subjected to the rotational operations, it is easier that theinsertion tube 13A of the first endoscope 13X be guided into theafferent loop F9 even when the positional fixing function given by theballoon 55 is not utilized. Like the first embodiment, it is thuspossible to allow the insertion tube 13A to pass through the thin andlong afferent loop F9. As a result, the present embodiment can providethe similar operations and advantages to those explained in the firstembodiment.

Of course, the insertion tube 13A of the first endoscope 13X may be bentand inserted into the afferent loop F9 with the parallel use of thepositional fixing function of the balloon 55 to the jejunum F4.

The foregoing configuration described in the second embodiment can bereduced into practice in further various modified modes. Thosemodifications will be exemplified below, in which the same or identicalconfigurations to those in the first or second embodiments, or othermodifications are given the same reference numerals, with thedescription thereof omitted or simplified.

(First Modification)

FIG. 15 shows a first modification, which is concerned with an exampleshowing how to operate the foregoing overtube 51.

In the foregoing second embodiment, the overtube 51 is inserted into theafferent loop F9 with the use of, as a guide, the insertion tube 13A ofthe first endoscope 13X. For this insertion, under X-ray fluoroscopy, anoperator inserts the overtube 51 into the jejunum F4 (FIG. 15(A)), androtates the overtube 51 in such a manner that an edge EG' of the distalend portion 51A (i.e., the distal-end-side edge of the oblique opening)is oriented toward the jejunum-to-jejunum anastomosed portion F5 (FIG.15(B)). And, as shown in FIG. 15(B), when the opposite-side edge EG ofthe distal end portion 51A (i.e., the at-hand-side edge of the obliqueopening) enters the inlet of the jejunum-to-jejunum anastomosed portionF5, the overtube 51 is rotated by 180 degrees on its axial direction.Thus, as shown in FIG. 15(C), the distal-end-side edge EG′, which facesthe edge EG, is located on the outer-circumferential wall side insidethe afferent loop F9. Accordingly, the edge EG′ of the distal endportion 51A touches a lower side part N of the jejunum-to-jejunumanastomosed portion F5, so that the overtube 51 can be pushed forwardwith the use of the edge EG′ as a fulcrum, enabling the overtube 51 tobe inserted more easily along the afferent loop F9. Additionally, sincethe distal-end-side edge EG′ receives a support from thejejunum-to-jejunum anastomosed portion F5, the overtube 51 can beinserted in an uneasy-to-be pulled manner.

(Second Modification)

FIG. 16 shows a second modification, which concerns another structure ofthe foregoing overtube 51.

An overtube 61 shown in FIG. 16 is similar in structure to the overtube51 descried, except that the flexible tubular portion 52 is subjected touneven thickness formation (refer to FIG. 16(A)). Practically, as theposition approaches to the at-hand-side edge EG of the distal endportion 51A with the oblique opening, the thickness of the tube becomeslarger. Thus, besides the operations and advantages obtained by theforegoing second embodiment, when the overtube 51 is inserted in thedirection shown in FIG. 16(B), the overtube 51 is given an improvedresistance against buckling performance.

(Third Modification)

FIG. 17 shows a third modification, which also concerns anotherstructure of the foregoing overtube 51.

As shown in FIG. 17, an overtube 71 is similar in structure to theovertube 51 descried, except that its distal end part including thedistal end portion 51A is bent previously. Thus the distal end of theovertube 71 is directed inward positively, facilitating the insertion ofthe overtube 71 into the afferent loop F9. In addition, a marker M1 thatindicates the bent direction is put on the grip 53, which provides theovertube 71 with a more facilitated insertion into the afferent loop F9,on top of the operations and advantages similar to those in the secondembodiment.

(Fourth Modification)

FIG. 18 shows a fourth modification, which concerns another example ofthe second endoscope 13Y.

As shown in FIG. 18, on the at-hand-side outer surface of the insertiontube 13A of the second endoscope 13Y, a marker M2 is put, which is usedby an operator to know an amount of protrusion of the distal end portion45 of the insertion tube 13A which is protruded from the distal end ofthe overtube 11 by an operator. The overtube applied to thismodification may be the one employed in the second embodiment and itsmodifications.

Thus, besides the operations and advantages similar to those in thefirst and second embodiments, the present modification has a merit thatit is made clearer that how much the second endoscope 13Y should beinserted into the overtube 11 for a treatment of pancreatic and biliaryducts or other treatments, i.e., a target amount for the insertion isshown clearer, making the insertion easier.

(Fifth Modification)

FIG. 19 shows a fifth modification, which concerns another structure ofthe overtube.

An overtube 81 shown in FIG. 19(A) has not only the same structure asthat of the overtube 51 shown in FIG. 12 but also a slit 56 along anaxial area ranging from the flexible tubular portion 52 to the grip 53(refer to FIG. 19(B)). Incidentally this overtube 81 has no balloon.

In this modification, for inserting the first endoscope 13X into theovertube 81, it is possible that the endoscope 13X is loaded in theovertube 81 from its side, not from the distal end of the endoscope 13X.Accordingly, the insertion (loading) can be made easier.

(Sixth Modification)

FIGS. 20 and 21 show a sixth modification, which still concerns anotherstructure of the overtube.

An overtube 91 shown in FIG. 20 comprises a flexible tubular portion 92made of resin material and having flexibility, a grip 93 formedintegrally with an at-hand-side end of this flexible tubular portion 92,and an air-supply mouth ring 94A and a water-supply mouth ring 94B bothformed from the flexible tubular portion 92. Furthermore, through a sidewall residing in a distal end part of the flexible tubular portion 92, aslit-shaped side opening 92A with a predetermined length is opened alongits axial direction. Incidentally it is not always necessary to load aballoon on this overtube 91.

Thanks to the structure above, the operation for inserting the firstendoscope 13X into the afferent loop F9 can be made easier.Specifically, as shown in FIG. 21(A), the overtube 91 is positioned at aposition adjacent to the jejunum-to-jejunum anastomosed portion F5 underimages the first endoscope 13X. Then, as shown in FIG. 21(B), theovertube 91 is pushed to advance by a predetermined distance so that theside opening 92A faces the jejunum-to-jejunum anastomosed portion F5,that is, the inlet of the afferent loop F9. Then the insertion tube 13Aof the endoscope 13X is pulled back and bent so as to make the distalend portion 45 protrude from the side opening 92A. Since the protrudedposition is present just at the inlet of the afferent loop F9, theinsertion tube 13A is simply pushed to pass along the afferent loop F9without any other actions, as shown in FIG. 21(C), whereby the insertiontube 13A can be passed there easily. As being flexible, the overtube 91can be pushed and made to advance along the afferent loop F9 with theuse of the insertion tube 13A as a guide member. In this insertingoperation, twisting the overtube 91 makes the insertion easier (FIG.21(D) and 21(E)).

Accordingly, similarly to the second embodiment, passing the endoscope13X along the afferent loop F9 can be facilitated.

(Seventh Modification)

FIGS. 22-24 show a seventh modification, which still concerns anotherstructure of the overtube.

An overtube 101 shown in FIG. 22 comprises a flexible tubular portion102 made of resin material and having flexibility, a grip 103 formedintegrally with an at-hand-side end of this flexible tubular portion102, and an air-supply mouth ring 104A and a water-supply mouth ring104B both formed from the flexible tubular portion 102. Furthermore,through a side wall residing in a distal end part of the flexibletubular portion 102, a slit 102A with a predetermined length is openedalong its axial direction to communicate with the distal end opening.Incidentally it is not always necessary to load a balloon on thisovertube 91. A balloon 105 similar to that has been described already isequipped at a distal-end-side predetermined position on the flexibletubular portion 102. The balloon 105 can be expanded and shrunk byselectively supplying to and discharging air from the air-supply mouthring 104A.

Hence, when the second endoscope 13Y (side-viewing endoscope) issubjected to insertion for a treatment of pancreatic and biliary ducts,a back portion BK and side portions SD of the distal end portion of theovertube 101, which are other than the side opening 102A, positionallyrestrains the second endoscope 13Y, as shown in FIGS. 23 and 24. It istherefore easier to sustain the position of the distal end portion 45relative to the Vater's papilla F8. In this restrained state as shown inFIG. 24, the second endoscope 13Y is elevated appropriately for thetreatment of pancreatic and biliary ducts.

(Eighth Modification)

FIGS. 25-26 show an eighth modification, which still concerns anotherstructure of the overtube.

An overtube 111 shown in FIG. 25 comprises a flexible tubular portion112 made of resin material and having flexibility and a grip 113 formedintegrally with an at-hand-side portion of the flexible tubular portion112. The flexible tubular portion 112 includes a distal end portion112A, a bendable portion 112B formed adjacently to the distal endportion 112A and formed to have a predetermined axial length, and awater-supply mouth ring 104B positioned at a base-end-side predeterminedposition. The bendable portion 112B is structured to be bendableactively toward either up/down/right/left four directions (when viewedalong the axial direction) or any two of the four directions by towforces of wires (not shown). In FIG. 25, an operation lever 114 isattached to the grip 113, which operation lever 114 is for bending thebendable portion 112B in the two directions. Handling this operationlever 114 allows the wires (not shown; inserted to axially pass theflexible tubular portion 112) to give tow forces to the bendable portion112B. Thus the bendable portion 112B can be bent in response to anoperator's demand.

Thus, with the first endoscope 13X inserted through the insertionchannel P1 of the overtube 111, the overtube 111 is orally inserted intothe body. When the endoscope 13X reaches a predetermined position whereforward-viewing endoscopic images capture the jejunum-to-jejunumanastomosed portion F5, the endoscope 13X is temporarily stopped frombeing inserted (refer to FIG. 26(A)). Then, as the overtube 111 ispushed to advance, the operator handles, in parallel with theadvancement, the operation lever 114 to bend the bendable portion 112Bat an almost right angle to be oriented toward the jejunum-to-jejunumanastomosed portion F5 (refer to FIG. 26(B)). As a result, the distalend portion 112A of the overtube 111 can be inserted deeply along theafferent loop F9, together with the distal and portion 45 of theinsertion tube 13A of the first endoscope 13X (refer to FIG. 26(C)).

Incidentally, it is not always true that the overtube 111 is providedwith the balloon. But when such a balloon is needed, it is preferredthat the balloon is provided at a base-end-side part of the bendableportion. In the case that the balloon is equipped on the overtube 111,the positional fixing function given by the balloon may be used togetherin the insertion state shown in FIG. 26(A).

(Ninth Modification)

FIGS. 27-28 show a ninth modification, which still concerns anotherstructure of the overtube.

An overtube 121 shown in FIG. 27 is equipped with a cylindricalresin-made outer tube 122 having an insertion channel and a resin-madeinner tube 123 to be inserted through the insertion channel of the outertube 122.

Of these tubes, the outer tube 122 includes a resin-made flexibletubular portion 131 having flexibility and a grip 132 formed integrallywith an at-hand-side end of the flexible tubular portion 131. Theflexible tubular portion 131 includes a distal end portion 131A and abendable portion 131B positioned next to the distal portion 131A andformed to have a predetermined axial length. This bendable portion 131Bis structured to be bendable actively for example in theup/down/right/left four directions or any two of the four directions(when viewed along the axial direction) by tow forces of wires (notshown). In the structure shown in FIG. 27, the bendable portion 131B canbe bent in two directions by handling an operation lever 133 attached tothe grip 132. Handling the operation lever 133 allows wires to give towforces to the bendable portion 131B, which wires are inserted to axiallypass the flexible tubular portion 131. Thus the operator is able to bendthe bendable portion 131B according to operator's demand.

The similar structure is true of the inner tube 123. That is, the innertube 123 includes a resin-made flexible tubular portion 141 havingflexibility and a grip 142 positioned next to the at-hand-side end ofthe flexible tubular portion 141. Further, the flexible tubular portion141 includes a distal end portion 141A and a bendable portion 141Blocated next to the distal end portion 141A to have a axialpredetermined length. The bendable portion 141B is structured to bebendable actively for example in the up/down/right/left four directionsor any two of the four directions (when viewed along the axialdirection) by tow forces of wires (not shown). An operation lever 143 tohandle the bendable portion 141B is attached to the grip 142. Handlingthe operation lever 143 enables the wires, which axially pass theflexible tubular portion 141, to give tow forces to the bendable portion141B, which can be bent according to operator's demand.

References 104B′ and 104B″ in FIG. 27 represent a water-supply mouthring, respectively.

Hence, with the first endoscope 13X inserted through the insertionchannel P1 of the overtube 121, the overtube 121 is orally inserted,during which forward-viewing images capture the jejunum-to-jejunumanastomosed portion F5 at a predetermined inserting position, whereatthe insertion is temporarily stopped (refer to FIG. 28(A)). Then theoperator handles the operation lever 133 of the outer tube 122 so thatthe bendable portion 131B is bent at an almost right angle to bedirected toward the jejunum-to-jejunum anastomosed portion F5,concurrently with operations to make the outer tube 122 advance (referto FIG. 28(B)).

Thus, together with the distal end portion 45 of the insertion tube 13Aof the first endoscope 13X, the distal end portion 131A of the outertube 122 (and the inner tube 123) can be inserted deeply along theafferent loop F9. When the outer tube 122 is inserted to some extentinto the afferent loop F9, the operator makes the inner tube 123protrude from the outer tube 122, while the inner tube 123 is bent(refer to FIG. 28(C)). Hence, the distal end of the inner tube 123almost reaches a deep position in the afferent loop F9, which deepposition is nearly the end of a curve of the afferent loop F9. Afterthis, the operator extends the first endoscope 13X from the distal endof the inner tube 123 along the afferent loop F9.

In this way, the outer tube 122 is in charge of performing the bentoperation needed to intrude into the afferent loop F9, the inner tube123 is in charge of running to finish almost the jejunum-to-jejunum bentportion F6 which is a primary curve of the afferent loop F9, and thenthe endoscope 13X is in charge of running along a final moderate curvedpart of the duodenum F7. That is, the relatively thin, long, and sharpcurve of the afferent loop F9 is covered by the three-step relayingbending operations. Hence the degree of bending necessary in each stepis not so sharp, enabling the overtube 121 and the insertion tube 13A ofthe endoscope 13X to pass the afferent loop F9 smoothly and steadily.

In addition, the overtube 121 may not always be equipped with a balloon.When the balloon is equipped on the overtube 121, it is preferred thatthe balloon is present at a base-end-side part of the bendable portion.

Of course, a balloon may be equipped on the outer tube 122 of theovertube 121 to utilize the positional fixing function on the balloon inthe state shown in FIG. 28(A).

(Tenth Embodiment)

FIG. 29 shows a tenth modification, which concerns a modified form(positioning) of the overtube 121 shown in FIG. 27, which is accordingto the ninth modification.

Specifically, as shown in FIG. 29, to achieve the positioning betweenthe outer and inner tubes 122 and 123 in the circumferential directionaround the axial direction, markers are adopted. A marker M3 is put onthe grip 132 of the outer tube 122, while a marker M4 is put on the grip142 of the inner tube 123. Matching these markers M3 and M4 with eachother leads to positioning both tubes 122 and 123 in the circumferentialdirection, whereby the bending directions thereof can be matched witheach other. In addition, the length of the inner tube 123 protruded fromthe outer tube 122 can be measured.

(Eleventh Modification)

FIGS. 30-31 show an eleventh modification, which concerns a modifiedform (lock mechanism) of the overtube 121 shown in FIG. 27, which isaccording to the ninth modification.

Practically the overtube 121 includes the outer and inner tubes 122 and123, as described already. Inside the grip 132 of the outer tube 122, anelastic ring 151 is incorporated which exhibits a higher frictioncoefficient relative to the outer surface of the flexible tubularportion 141 of the inner tube 123. This elastic ring 151 can be pusheddetachably by a knob 152 that engages with a thread formed on the innersurface of the grip 132.

Hence, as shown in FIG. 31(A), when the knob 152 is loosened, theelastic ring 151 is not pushed, so that the inner diameter of theelastic ring 151 is larger. In this state, the inner tube 123 passes andmoves through the insertion port of the outer tube 122 without anyinterference. Tightening the knob 152 causes a reduction in the innerdiameter of the elastic ring 151 as shown in FIG. 31(B), thus enablingthe inner wall portion to push the inner tube 123.

Therefore, the inner and outer tubes 123 and 122 can be locked with eachother at a desired position in the axial and circumferential directions.

Incidentally, this lock mechanism is not limited to the applicationemployed between the outer and inner tubes of the overtube. Forinstance, as a locking means, this lock mechanism can also be appliedbetween the overtube and an endoscope to be inserted. In such a case,the foregoing elastic ring and knob are loaded on the overtube, in whichthe lock function is given to the insertion tube of the endoscope.

(Twelfth Modification)

FIGS. 32-33 show a twelfth modification, which still concerns a furthermodified form of the overtube. In particular, this modification concernsan overtube, which is equipped with outer and inner tubes, providing theendoscope with a guide during passing the sharpest curve of the afferentloop F9, i.e., a part ranging from the jejunum-to-jejunum anastomosedportion F5 to the jejunum-anastomosed bent portion.

As shown in FIG. 32, an overtube 151 is equipped with an outer tube 152and an inner tube 153. The outer tube 152 includes a flexible tubularportion 161 having an insertion channel and a grip 162 formed integrallywith an axial base-side end of the flexible tubular portion 161. At adistal-side predetermined position of the flexible tubular portion 161,a side opening 161A is formed in the axial direction thereof. The innertube 153 is made of a resin and has a high flexibility, and is subjectedto insertion into the insertion channel of the outer tube 152. Like theforegoing, the inner tube 153 includes a flexible tubular portion 171having an insertion channel and a grip 172 formed integrally with anaxial base-side end of the flexible tubular portion 171. At adistal-side predetermined position of the flexible tubular portion 171,a side opening 171A is formed in the axial direction thereof.

The insertion tube 13A of the first endoscope 13X or the secondendoscope 13Y, which is selected, is inserted into the insertion channelof the inner tube 153.

Practically, in a state where the first endoscope 13X is insertedthrough the insertion channel of the inner tube 153 and the inner tube153 is inserted through the insertion channel of the outer tube 152, anoperator observes forward-viewing endoscopic images, during which timethe operation inserts orally the overtube 151 and the first endoscope13X to reach the jejunum-to-jejunum anastomosed portion F5. That is, asshown in FIG. 33(A), the outer tube 152 reaches a predetermined positionjust before the jejunum-to-jejunum anastomosed portion F5. Then, asshown in FIG. 33(B), the operator pulls back the first endoscope 13X sothat the distal end of the first endoscope 13X is hidden within theinner tube 153, and the operator manually rotates the outer tube 152 toorient its side opening 161A toward the jejunum-to-jejunum anastomosedportion F5, i.e., the inlet of the afferent loop F9. This operationallows the side opening 161A and the inlet of the afferent loop F9 to bepositioned with each other.

After this, as shown in FIG. 33(C), the operator pushes the inner tube153 by a predetermined length from the side opening 161A of the outertube 152 toward the afferent loop F9. By this operation, the inner tube153 is allowed to reach almost half the jejunum-anastomosed bent portionF6. This inner tube 153 has a sufficient flexibility, the inner tube 153can be reached deeply, as shown in the figure, as almost half as thejejunum-anastomosed bent portion F6 reasonably, without positive bendingactions like the present example. Of course, the inner tube 153 may bebent positively for insertion or a slit may be formed to make it easierthat the inner tube is bent further passively.

When the insertion of the inner tube 153 is completed, the operatorextends the first endoscope 13X, from the side opening 171A of the innertube 153, along the remaining part of the afferent loop F9 (refer toFIG. 33(D)). Since being already guided until almost half of theafferent loop F9 by the outer and inner tubes 152 and 153, it is easierfor the first endoscope 13X to advance continuously from the formerinsertion. Thus this endoscope 13X can be extended to reach the Vater'spapilla F8, with imaging and treatments performed necessary thereat.

When the second endoscope 13Y is fed instead of the first endoscope 13X,the guide path already provided by the outer and inner tubes 152 and 153can be used to allow the second endoscope 13Y to pass through theafferent loop F9 so as to reach the Vater's papilla F8 smoothly in ashort period of time.

As a result, like the foregoing embodiments and modifications, it ispossible that the endoscope 13 is able to pass, smoothly and easily, therelatively thin and longer afferent loop F9 with the inlet almostperpendicular to the jejunum F4. The insertion can be facilitated.

Incidentally when a balloon is put on the distal end portion of theinner tube 153, the balloon may be expanded, in the state of FIG. 33(D),to be fixed positionally to the inner wall of the afferent loop F9. Thispositional fixing provides a fulcrum to assist the extension of thefirst endoscope 13X.

(Thirteenth Modification)

FIGS. 34-35 show a thirteenth modification, which still concerns afurther modified form of the twelfth modification. Part of the referencenumerals used in this modification is diverted from those of the twelfthmodification.

In the thirteenth modification, the overtube 151 has the outer tube 152and an inner tube 153′. In particular, as shown in FIG. 34, the innertube 153′ has no side opening.

According to this configuration, as shown in FIG. 35(A)-(D), the similaroperations and advantages to those in the foregoing twelfth modificationcan be obtained. Particularly, as understood from FIG. 35(C), (D), whilethe insertion tube 13A of the first endoscope 13X is made to advancefrom the frontal opening of the inner tube 153′ while the insertion tubeis bent. This allows the overtube 151 to smoothly advance along thejejunum-to-jejunum anastomosed portion F5 and the jejunum-anastomosedbent portion

F6.

Further, the inner tube 153′ can be made to advance further by runningit on and along the insertion tube 13A, so that, like the firstembodiment, it is possible to provide endoscope guide means till avicinity of the Vater's papilla F8 by using the combination of the outertube 152 and the inner tube 153′.

(Fourteenth Modification)

FIGS. 36-37 show a fourteenth modification, which still concerns afurther modified form of the twelfth modification. Part of the referencenumerals used in this modification is diverted from those of the twelfthmodification.

In the fourteenth modification, the overtube 151 comprises the outertube 152 and an inner tube 153′. Specifically, as shown in

FIG. 36, the inner tube 153″ has a slit 153S formed at the distal endportion thereof and formed to extend to have a predetermined lengthcontinued from the frontal opening.

According to this configuration, as shown in FIG. 37(A)-(D), the similaroperations and advantages to those in the foregoing twelfth modificationcan be obtained. Particularly, as understood from FIG. 37(C), (D), whilethe insertion tube 13A of the first endoscope 13X is made to advancefrom the slit 153S of the inner tube 153′ while the insertion tube isbent.

This provides the similar operations and advantages to those in thethird modification.

Incidentally, the scope of the present invention will not be limited tothe configurations described in the foregoing embodiments and theirvarious modifications, but the present invention may be reduced intopractice in appropriate modes combined with conventional knownstructures, without departing from the scope of the present inventiondescribed in the appended claims.

1. An endoscopic system comprising: an overtube having an insertionchannel formed along an axial direction thereof; an endoscope insertedinto the insertion channel of the overtube for use thereof; and assistmeans for assisting, when the overtube is inserted adjacently to ajejunum-to-jejunum anastomosed portion of a jejunum of an object beingexamined in a state where the endoscope is kept being inserted into theinsertion channel of the overtube, changes of an insertion path alongwhich the overtube is inserted from the jejunum to thejejunum-to-jejunum anastomosed portion.
 2. The endoscopic system ofclaim 1, wherein the assist means comprises a balloon that positionallyfixes the overtube onto the jejunum, the balloon being loaded to anouter surface of the overtube and expanded by supplying air thereto sothat the balloon comes into contact with the jejunum.
 3. The endoscopicsystem of claim 1, wherein the assist means is an oblique opening thatis formed at a distal end portion of the overtube and that is oblique toan axial direction of the overtube, wherein, when the distal end portionof the overtube reaches the jejunum-to-jejunum anastomosed portion, theovertube is rotated on the axial direction so that the oblique openingis directed towards the jejunum-to-jejunum anastomosed portion.
 4. Theendoscopic system of claim 3, wherein the distal end portion is bent soas to direct the oblique opening towards a direction perpendicular tothe axial direction.
 5. The endoscopic system of claim 1, wherein theovertube has a slit formed entirely through the overtube in the axialdirection thereof.
 6. The endoscopic system of claim 1, wherein theassist means is either a side opening or a slit which is formed throughthe overtube and which allows an insertion tube of the endoscopeinserted in the insertion channel to advance towards a radial directionperpendicular to the axial direction.
 7. The endoscopic system of claim1, wherein the assist means is a bendable portion which is formed at theovertube and bent in response to operations so as to enable a distal endportion of the overtube to be changed in a direction thereof.
 8. Theendoscopic system of claim 1, wherein the overtube is made up of aninner tube into which the endoscope is inserted and an outer tube intowhich the inner tube is inserted.
 9. The endoscopic system of claim 1,wherein the endoscope is marked by a marker indicative of an amount bywhich a distal end portion of an insertion tube of the endoscope isprotruded from an distal end of the overtube in a state where theovertube is inserted.
 10. The endoscopic system of claim 8, wherein theassist means is a bendable portion which is formed at the outer tube andbent in response to operations so as to enable a distal end portion ofthe outer tube to be changed in a direction thereof.
 11. The endoscopicsystem of claim 10, wherein the inner tube comprises a bendable portionwhich is bent in response to operations so as to enable a distal endportion of the inner tube to be changed in a direction thereof.
 12. Theendoscopic system of claim 8, wherein each of the inner tube and theouter tube has a marker for mutually positioni ng both inner and outertubes in a circumferential direction around the axial direction.
 13. Theendoscopic system of claim 8, comprising lock means for positionallylocking both inner and outer tubes in the axial direction.
 14. Theendoscopic system of claim 1, wherein the endoscope is either aforward-viewing endoscope or an oblique-viewing endoscope which allowsthe overtube to be guided from the jejunum to a target portion via thejejunum-to-jejunum anastomosed portion.